The Glucocorticoid Resistance Syndrome. Two Cases of a Novel Pathogenic Variant in the Glucocorticoid Receptor Gene.

Glucocorticoid resistance syndrome is a rare genetic condition characterized by generalized or partial target-tissue insensitivity to glucocorticoids and a consequent hyperactivation of the hypothalamic-pituitary-adrenal axis. Clinical manifestations may include mineralocorticoid and/or androgen excess without manifestations of Cushing syndrome. At a cellular level, glucocorticoid actions are mediated by the nuclear glucocorticoid receptor encoded by the NR3C1 gene. To date, only 33 glucocorticoid receptor loss-of-function pathogenic variants have been associated with glucocorticoid resistance syndrome. The NR3C1 gene has 2 known disease-causing mechanisms: haploinsufficiency and negative dominance. We describe a mother and her son with a mild hyperandrogenic phenotype and a novel genetic variant of the NR3C1 gene predicting a truncated protein and causing glucocorticoid resistance syndrome. To date, no accurate genotype-phenotype correlation has been found.